The present invention relates to recloseable openings, such as for flexible bags. Particularly, the present invention relates to a closure strip using a resealable adhesive portion which at least partly defines a recloseable opening, the closure strip attached to a wall of a flexible bag.
Closure strips for recloseable bags are generally known. One type of closure strip includes interlocking profile strips which typically include interlocking tongue and groove elements to seal a bag opening, such as described in U.S. Pat. Nos. 4,756,629, 5,806,984 or 4,909,017.
Another type of closure strip uses a resealable adhesive strip. The resealable adhesive strip uses a removable pressure sensitive adhesive to close a bag opening. A xe2x80x9cremovable pressure sensitive adhesivexe2x80x9d is one which can be peeled off, together with the backing to which it is applied, from a substrate surface without damage to either the adhesive or the substrate. U.S. Pat. Nos. 5,035,518; 4,645,711; 4,599,265; 4,629,663; 3,608,707; 3,922,464; 4,902,142; and 4,709,399, describe pressure sensitive adhesives and/or packaging using pressure sensitive adhesives.
One drawback to interlocking profile strips is that the strips are relatively thick compared to the thickness of the web material which comprises the front and back wall of the associated bag. This relatively increased thickness is required in order to form the interlocking tongue and groove of the interlocking profile strips. The increased thickness of the profile strip requires higher sealing temperature, pressure and dwell time in the formation of the bag. These additional considerations adversely affect the speed and throughput of the bag forming machines.
Resealable adhesive strips suffer the drawback that the strips lack a positive closing which gives the user indication or xe2x80x9cfeedbackxe2x80x9d of a complete closure of the resealable bag.
The present inventor has recognized that it would be advantageous to provide a recloseable strip for a bag that has a low profile thickness and which also provides a positive closure indication to the user.
The present invention provides a recloseable closure strip for an opening, such as for a flexible bag. The closure strip includes an adhesive region and at least one flexible member which deflects during engagement of the adhesive region to an adhesive receiving region of the bag during re-sealing. The deflection of the flexible member provides a positive closing indication or feedback to the user during re-sealing.
The flexible member can be part of a resilient structure which carries the adhesive region such that by engaging the closure strip to reclose the bag, the resilient structure is compressed or squeezed from a relaxed or uncompressed condition to a flattened condition, giving the user a positive feel or indication of the re-sealing of the bag opening. The resilient structure can be significantly thinner in profile than the prior known interlocking profile strips due to the fact that it is functioning only as an indication of sufficient re-sealing pressure and does not perform a sealing function.
The bag can include a companion strip to the closure strip, the companion strip providing an adhesive receiving area or xe2x80x9clandxe2x80x9d for the adhesive region of the closure strip. The companion strip can be plain or can have a coacting adhesive applied thereto. The adhesive region of the closure strip and the land of the companion strip can include, rather than tacky adhesives, cold sealable, pressure sensitive cohesives which are adherent to each other and are not tacky and adherent to other surfaces.
The closure strip of the invention can include interlocking elements which interlock when the resilient structure is compressed to its flattened condition simultaneously with the adhesive strip contacting the land, to give the user a positive indication of the re-sealing of the bag opening. The resilient structure can include a base portion and a wing portion, one of which is connected to a first wall of the bag, the wing portion extending obliquely from the base portion, and the base portion carrying the adhesive strip. The interlocking elements can be applied one on the base portion and one on the wing portion to interlock when the base portion and the wing portion are flattened together.
The interlocking portions function differently than that of conventional closures since they do not lock the closure, but instead only give the closure the same xe2x80x9cfeelxe2x80x9d or indication of re-sealing as do interlocking closures, but which utilizes an adhesive as the re-sealing means with the adhesive acting independently of the interlocking action of the interlocking portions.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.